- Preparation method of phenoxycarboxylic acid choline salt
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The invention provides a preparation method of a phenoxycarboxylic acid choline salt, wherein the preparation method includes the steps: S1, carrying out condensation reaction of phenol or o-cresol with chlorocarboxylic ester in the presence of alkaline substances to obtain phenoxycarboxylic ester; S2, carrying out selective chlorination of the phenoxycarboxylic ester with a chlorinating agent inthe presence of a first catalyst and a second catalyst to obtain chlorobenzoxycarboxylic ester; and S3, after reaction of trimethylamine with ethylene oxide, adding the chlorophenoxycarboxylic acid ester, and carrying out alkaline hydrolysis reaction to obtain the phenoxycarboxylic acid choline salt. Compared with a conventional synthesis technology, the preparation method effectively avoids the production and use of chlorophenols with unpleasant odor, radically eliminates the production of highly toxic dioxins, and greatly improves the product quality and the operation environment of the production site; with phenol as the raw material, through condensation, selective chlorination and alkaline hydrolysis, the high-quality phenoxycarboxylic acid choline salt is obtained, the loss of effective ingredients is effectively avoided and the yield of the product is increased.
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- Preparation method for 2,4-dichlorophenoxyacetic acid
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The invention provides a preparation method for 2,4-dichlorophenoxyacetic acid. The preparation method comprises the following steps: A) reacting C2 or above-C2 alcohol with halogenated acetic acid soas to obtain halogenated acetate; B) reacting halogenated acetic acid with 2,4-dichlorophenolate so as to obtain 2,4-dichlorophenoxyacetate; and C) hydrolyzing 2,4-dichlorophenoxyacetate so as to obtain 2,4-dichlorophenoxyacetic acid. According to the invention, C2 or above-C2 alcohol reacts with halogenated acetic acid to obtain a halogenated acetate intermediate, the intermediate has good stability, few reaction by-products are produced, and high yield is realized; then the intermediate further reacts with 2,4-dichlorophenolate to obtain 2,4-dichlorophenoxyacetate; and finally, 2,4-dichlorophenoxyacetate is hydrolyzed to obtain 2,4-dichlorophenoxyacetic acid. Through a specific reaction route of the invention, the finally prepared 2,4-dichlorophenoxyacetic acid has high purity and yield, few by-products are produced, the reaction route is simple, and the application of the preparation method is facilitated.
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- A method for preparing 2, 4 - dichlorophenoxyacetic acid (by machine translation)
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The invention provides a 2, 4 - dichlorophenoxyacetic acid preparation method, comprises the following steps: A) halogenated acetate with 2, 4 - dichlorophen salt reaction, to obtain 2, 4 - dichlorophenoxy ester; B) 2, 4 - dichlorophenoxy ester under the effects of catalyst hydrolysis reaction, to obtain 2, 4 - dichloro acid; said catalyst is selected from a polyether, a crown ether, quaternary ammonium salt, tertiary amine, [...], pyridine, titanate, inorganic acid, in organic acid one or more. The invention by halogenated acetate with 2, 4 - dichlorophen salt obtained by reaction of 2, 4 - dichlorophenoxy ester, and then in particular under the action of catalyst by hydrolysis reaction of the 2, 4 - dichloro acid. The invention specific reaction line combined with a specific catalyst such that the final preparation to obtain 2, 4 - dichlorophenoxyacetic acid purity and yield is relatively high, few by-products, the reaction route is simple, and is favorable for application. (by machine translation)
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Paragraph 0050; 0051
(2018/09/08)
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- Preparation method of 2,4-dichlorophenoxyacetic acid and salt thereof
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The invention provides a preparation method of 2,4-dichlorophenoxyacetic acid and a salt thereof, wherein the preparation method includes the following steps: S1) carrying out a reaction of phenol andchloracetic ester under alkaline conditions to obtain phenoxyacetic ester; S2) carrying out selective chlorination reaction of the phenoxyacetic ester with a chlorinating agent under the action of acatalyst A and a catalyst B to obtain 2,4-dichlorophenoxyacetic ester, wherein the catalyst A is Lewis acid, and the catalyst B is C5-22 thioethers, thiazoles, isothiazoles and thiophenes or halogenated derivatives thereof; and S3) carrying out hydrolysis reaction of 2,4-dichlorophenoxyacetic ester under acidic conditions to obtain 2,4-dichlorophenoxyacetic acid; or after 2,4-dichlorophenoxyaceticester is obtained, carrying out an alkaline hydrolysis reaction with an alkaline compound to obtain 2,4-dichlorophenoxyacetate. The production and use of 2,4-dichlorophenol with unpleasant odor are avoided, the production of dioxins is eliminated, the yield of products is improved, and the output of three wastes is greatly reduced.
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Paragraph 0111; 0113
(2019/01/06)
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